在Java中连接两个字符串的最快方法是什么? [英] What's the fastest way to concatenate two Strings in Java?
问题描述
在Java中连接两个字符串的最快方法是什么?
What's the fastest way to concatenate two Strings in Java?
ie
String ccyPair = ccy1 + ccy2;
我使用 cyPair
作为密钥在一个 HashMap
中,它在一个非常紧凑的循环中被调用以检索值。
I'm using cyPair
as a key in a HashMap
and it's called in a very tight loop to retrieve values.
当我描述然后这是瓶颈
java.lang.StringBuilder.append(StringBuilder.java:119)
java.lang.StringBuilder.(StringBuilder.java:93)
推荐答案
这些例程之所以如此在基准测试中出现是因为这就是编译器如何实现你的+。
The reason why these routines show up in the benchmark is because that is how the compiler implements your "+" under the covers.
如果你真的需要连接字符串,你应该让编译器做它与+的魔力。如果您需要的是一个用于映射查找的键,一个包含具有合适的equals和hashMap实现的字符串的键类,可能是一个好主意,因为它避免了复制步骤。
If you really need the concatenated string, you should let the compiler do its magic with the "+". If you all need is a key for map lookup a key class holding both strings with suitable equals and hashMap implementations, might be a good idea as it avoids the copying step.
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